Toggle mechanism



J SNEED TOGGLE MECHANISM Orlglnal Flled March 16, 1929 Feb. 26, i935.

TOGGLE MECHANISM .Original Filed March 16, 1929 2 Sheets-Sheet 2 inve 111%01 dftozncq Patented Feb. 26, 1935 f `rrooien: MEcHANIsM John Sneed, .Grosse Pointe Shores, Mich., assignor to The Midland Steel' Products Company, Cleveland, Ohio, a corporation of Ohio, trustee for'Steeldr'aulic Brake Corporation; Detroit, Mich., a corporation of'Michigan Original application March 16, 1929, SerialNo.

Divided and this application .Septem- 'bei 29, 1931,.,seriai1vo. 565,749;

. .is claims. (o1. 18s-vs.) f

This invention relates to vehicle brakes. and has to do, more particularly, with a novel form` of expanding mechanism for separating the endsy of the brake shoe. y

co-pending application, Serial No. 347,515, led March 16, 1929, forVehicle brakes. n f It is among the objects of thisinvention to provide a spreading or shoe-expanding means which may be easily assembled or disassembled, which may be expeditiously mounted between the ends of the shoe or quickly knocked down and removed therefrom. v u

Another object of this invention is to provide, a spreading` or shoe-expanding means linwhich friction losses are reduced to a minimum Vand which has a novel arrangement of parts giving an additional range of movement beyond normal dead center of the toggle. A

,Y Another object of this-invention is toprovide a novel form of toggle for spreading the ends of the brake shoe that is extremely-'simple in con.- structionand which may beV readily and easily manufactured at a minimum cost. Another object of this invention is to provide a toggle that may be arranged between the shoe ends Without undue labor or a partial dismantling of the brake, thereby permitting thedevice to be readily inserted aswell as removed from between therends ofthe brake shoe for .the purposes of repair, in a manner that is equally expeditious. This invention contemplates a brake expanding device which takes the form of a toggle mechansm made up of toggle arms easilyiseparated for the purpose of removing at least a portion of the toggle `from co-operative engagement with the brake shoe. In its preferred Vform the toggle consistslof a male arm and a female arm, the male arm being pivotally connected to one ofthe shoe ends and having a bifurcatedportion. removably engaging with the toggle centerpin and a female arm thatpivotally engages Withthe center pin and removably engages the opposing shoe end. The center-pin is. operatively connected to the .flexible cable or other tension member for operating .the toggle mechanism.. o To knock down the'toggle it is only'necessary .to disengage the female arm from the thrust pin at its end of the shoe, thereby permitting'the center pin and toggle .to bel moved out of .engagement with the -bifurcated portion of the kmale arm, Then .the flexiblecable may be withdrawn from the apron. which allows the Withdrawal from 'the brake proper of that portion of the toggle attached thereto, To reassemble the toggle, the

This application constitutesa division ofv partsare replaced in a manner just the reverse of that''described'.y A Other and furtherobjects and advantageous features of this invention will. be hereinafter brought out, reference being had .to the accompanyng drav/ings'andy Written description, Wherein vlike clfiarac'te'rs of reference .designatecorresponding parts, and whereinz. fr' j l Fg..f1 is .an elevationlof'the assembled. parts constituting: the brake with. which .my novel form of'togle mechanism isfemployed.' I 1 ,1.,

`2` is a horizontal section takenlalongV illeJ unen-.2, Fig. `1. ".yligs. @and 4- are views similar to that of Fig.. 2,; .showingy the partsas'. they are .displaced during the spreading of the toggle-mechanism. Fig. 5 isa vertical. section taken alongl the line 5-..f5.o.f,Fg. 2. i `v f Fig. 6 is a viewshowing thek partsof thezto'ggle mechanism after separation.- I iv. Q I. Figf 7 isa viewsimilarto thatoff Fig. 6, showing'a portion of the'togglebcing' withdrawn trom theV brake. Y o. Fig. Sshows the endof the flexible cableand thev portionoi the toggle .mechanism secured thereto...` f

.Referring to the drawings, i particularly FigsL land 2, ,Il haveshown the` preferred'form. of my toggle .mechanism as'. mounted Ain'V conjunction with the usual drum D, Within which ispreferably kmounted a substantially annular brake shoe S l'carrying suitable .lining material, that. is adapted to be expanded into frictional engage-'-V ment With the brake drum. .Closing the` open iace of the drum and supporting the brake shoe is lan apron or backing plate A which`5ca`rries an anchor pin P with which the opposite .endsof the shoe engage in lidle position.` Dependingfupon' the direction of drum rotation, one` orthev other of the shoe ends will deliver brake torquato the anchor. This brake also includes an adjustor J carried by one end of the shoeand -ismovable circumferentially. thereof to varythe effective length ofsuch shoe. f

My toggle mechanism T is preferably-arranged in a` horizontal position between the endsV of the shoe and has its outer ends engaging with the thrust pinsel and 42 Imountedat such endsl 'respectively. yThe toggle serves .to force the vshoe vends apart and expand the brake into lengage-- ment with the drum. The mid-portion of `the toggle is connected to a flexible control C vincluding a cable and a exible conduitlthat Willbe vhereinafter described lEncore in detail along with vthe detail description .of the togglevv mechanism and yits operation. Of course, it will be understood that retractor springs are provided to draw the shoe onto the anchor and hold it out of contact with the drum when inidle position.

Such parts of the brake as the particular shoe, thek adjustor, the apron or backing plate, etc. have all been described more or less in detail in my co-pending application, Serial No. 347,515, filed March 16, 1929. Inasmuch as this description will be directed primarily thereto such parts as those just mentioned hereinabove will Vnot be dealt with in detail. i

Referring again to the toggle, it will be noted that it consists of a male arm 45 pivotally connected to a thrust pin 42 at one end and has its other end bifurcated as at 49,` Fig. `6, which bifurcated end slidably engages the toggle pivot pin 47. The female arm of the toggle, indicated by the numeral 46 comprises upper and lowerY parts lfolded overand joined together by portion 50, Fig; 7, which bridges both parts. The inner end of the female arm is pivotally connectedv to the toggle center pin 47 and has itsjouter end bifurcated asat 38 (Fig. 6) slidably and pivotally to engage a tlirust pin 4l, such pin beg disposed opposite the thrust pin 42 and being 'seated' in the adjustor J.

ends ofthe lfemale toggle arm 4 Y The inner ends of the toggle arms, as hereto-V before mentioned, engage a common pivot pin 47 which is in turn engaged by a yoke 48 connected to an actuating cable 60. Tension on the cable, see Figs. 2 and 3, tends to-ilatten the toggle and spread the shoe ends, at the same time exerting a lateral force through the pins 41 and 42 in the direction o f the apron. As the shoe ends are moved apart the rollers roll along the apron so that theshoe ends are spread with a mini,- mum ofv frictional resistance..` "j As mentioned, the male toggle arm'45 pivotally engages one ,end of the shoe, whereas the opposing end is bifurcated and pivotally and slidably engages the center pin of the toggle. However, the female arm 46 is pivotally and slidably engaged with the thrust pin 41 and is pivotally -mounted on the toggle center pin. This arrangement permits, in the assembly ofthe brake, the female toggle arm to be passed through an opening in the apron, Fig. 8, in `position t0 have its bifurcated end engage the thrust pin 41, and the male toggle arm is in such position as`to receive thepivot pin 47 of the toggle, see Fig. 6. To disassemble the parts' the procedure is necessarily the reverse, that is to say, .the yoke may be moved into the drum until such 'time as the bifurcated end 38 of the female arm disengages 'with the thrust pin 41 and the bifurcated end 49 of the male arm swings clear of the toggle center pin 47. Y, y

As hereinbefore related, the yoke 48 is secured to acable 60 and the brake is expanded by a force putting the cable in tension. IThis tends to expand theftoggle to a position, as that shown in either Fig. 3 or 4, in whichcontinued movement of the yoke might pull the toggle over dead center, thus rendering the brake inoperative. However, the extreme inner end 51 of the male arm 45 engages with the offset or bridge; 5,0 of the female arm 46 and further inward`movem`ent of the yoke changes the pivot point of the toggle from the axis of the pin 47 tothe point of Contact 52 between the parts 50 and 51 of the inner ends of the female and male toggle arms respectively. This prevents the toggle from being pulled over dead center and' the subsequent failure of the brake.

The yoke 48 is secured to a cable 60 which in turn carries at its vother end a connecting part 6l which may be secured to the brake operating linkage, carried by the chassis in the usual manner. The cable may be deemed part of the flexible control C, mentioned above, and considering the control as a whole, it also includes a flexible conduit or housing 62, cupped end fittings 55 and 56 and tubular'br'acket 67 detachably' secured to then apron. All of these parts have been separatelydescribed in myco -pending application, Serial No; 347,515, and will not be taken up in detail infthis application. Y l

Needless to say, with my improved form ef' toggle mechanism it will'be possible quickly andeasily to arrange the toggle between the-shoe ends in operative position. Likewise, it will be but a" simple matter toproduce the disengagement of the open ends of the male and female arms with their respective pivot pins'to permit the' disassem# bly4 of the toggle and the removal of the yoke 48n and the female arm 46 from the drum. The male arm, of course, remains within the drum by reason'of its pivotal engagement with the end of the brake shoe. y j

Thus it will be seen that my invention'lendsl itself to ease and economy of manufacture and assembly, as well as to increased safety and ease of operation of the brake. Whilev the foregoing describes a preferred form of my invention', modi-I fications and improvements may occur to those skilled in the art all within the major precepts `of my invention.l Thus I do not care to be limited to the specific disclosurev hereof or in any mannerother than bythe rclaims appended hereto.

` I claimz-` j `1. Spreading mechanism for a brake compris` ing atoggle having a center pivot pin and oppositely extending arms engaging said pin, one of said arms being pivotally and permanently engaged therewith and the other of said arms being pivotally, slidably and detachably engaged therewith.

2. Spreading mechanism for a brake compris-'- ing a toggle having a center pivot pin and oppositely extending arms engaging said pin, one of saidl arms khaving al bifurcated end for slidably engaging said pin, the other of said arms pivotally engaging saidl pin and having a bifurcated end adapted to slidably engage with a thrust pin on said brake. v

3. Spreading mechanism for a vehicle brake being demountably connected to' said-pin, the

other of said arms being demountably'connected to the opposing end of said brake shoe and permanently connected to the pin.

5. In combination a friction device, a toggle comprising a pair of arms for actuating the friction device and a control for actuating said toggle, one of the toggle arms being permanently pivotally connected to the friction device, the other of said arms being pivotally connected to the control and detachably connected to the first named toggle arm and constituting with said control a detachable sub-assembly.

6. A brake comprising a friction device, a toggle comprising a pair of arms actuating the friction device and a control for actuating said toggle, one of the toggle arms being pivotally connected to the friction device and detachably connected to the other of said arms, the other of said arms being pivotally connected to said control and detachably connected to said friction device and Vconstituting with said control a detachable sub-assembly.

'7. A toggle mechanism for spreading the ends of a brake shoe which comprises a center pivot pin having oppositely extending arms, one of said arms being connected to the end of the brake shoe and having a bifurcated end for slidably engaging the pin, both of said arms having parts near the pivot pin adapted to contact as the toggle approaches dead center for establishing a new pivot point to permit further expansion of the toggle.

8. Spreading mechanism for a brake comprising a toggle having a center pivot pin and oppositely extending arms engaging said pin, one of said arms having a bifurcated end for slidably engaging said pin, the other of said arms comprising two parts connected by an integral part near its inner end, the inner end of the first arm lying between the parts of the other arm and having a part engageable with the connecting part of the other arm to establish a secondary pivot point as the toggle approaches dead center.

9. In a brake the combination of a friction device having separable ends, toggle mechanism for spreading said ends including a pivot pin and arms extending from said pin to said separable ends of the friction device respectively, and a control for actuating said toggle pivotally and permanently attached to said pivot-pin, one of said toggle arms being pivotally and permanently attached to one of said separable ends of the friction device and slidably and removably attached to said pivot pin, the other of said arms being pivotally and permanently attached to said pivot pin and slidably and removably attached to the other of said shoe ends, both said arms having parts coacting prior to the approach of the toggle to dead center to prevent collapse thereof, and said control, toggle pin and toggle arm attached thereto comprising a separately re-v comprising a toggle having a center pivot pin and oppositely extending arms engaging said pin, one of said arms slidably engaging said pin, the other of said arms being permanently attached to said pivot pin and slidably connected to said brake, one of said arms having a part engageable with the other arm vto establish a secondary pivot point as the toggle'approaches dead center. v

12. Spreading mechanism for a brake comprising a, toggle having a center pivot pin and a pair of oppositely extending arms and means associated with at least one of said arms and cooperating with the other for establishing a secondary pivot point as the toggleapproaches dead center.

13. Spreading mechanism for a brake comprising a toggle having a center pivot pin, a control permanently attached to said pivot'pin, an arm permanently attached to said pivot pin and detachably connected to said brake, a second arm permanently connected to saidbrake and detachably connected to said pivot pin, and means for establishing a new pivot point for said toggle associated with at least one of said arms.

JOHN SNEED. 

